Component Having Boundary Element

ABSTRACT

A component having a boundary element is disclosed. In an embodiment a component comprises a semiconductor chip, a housing and a reflective layer, wherein the housing has a shaped body and a base body, the shaped body laterally enclosing the base body at least in places and being different from the reflective layer. In a plan view, the base body has a free area which is uncovered by the shaped body. The free area or a bottom surface of a cavity comprises a mounting surface for the semiconductor chip, wherein the semiconductor chip is arranged on the mounting surface. The bottom surface or the free area is partially covered by the reflective layer, wherein the mounting surface is enclosed at least in regions by a boundary element which adjoins the reflective layer and is configured to prevent the semiconductor chip from being covered by the reflective layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of German patent application 102017 117 628.4, filed Aug. 3, 2017, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

A component having high efficiency is provided. Furthermore, a methodfor producing such a component is provided.

BACKGROUND

In a component having a semiconductor chip and a housing, wherein thesemiconductor chip is disposed within a cavity of the housing, theelectromagnetic radiation generated by the semiconductor chip can beabsorbed at side walls of the cavity. In order to increase thereflectance of the side walls, the housing can be made of a materialcontaining reflective or scattering particles embedded therein. Sincethe material of the housing has to meet further requirements, forexample, with regard to breaking strength, tensile strength orcompressive strength, it is not possible to achieve a particularly highdegree of reflection on the side walls of the cavity. In order tofurther increase the performance of the component, a bottom surface ofthe cavity can be coated with a silver layer. However, such a metallayer corrodes easily, for example, by oxidation, so that itsreflectance decreases rapidly over time.

SUMMARY

Embodiments provide a component having high efficiency. Furtherembodiments provide a simplified method for producing such a component.

According to at least one embodiment of a component, it has asemiconductor chip, a housing and a reflective layer. The reflectivelayer may be electrically insulating. The housing has a shaped body anda base body, wherein the shaped body laterally encloses the base body atleast partially or completely. In particular, the shaped body isdifferent from the reflective layer. The shaped body can be configuredto be radiation-absorptive with regard to the electromagnetic radiationgenerated during operation of the semiconductor chip. The base body canbe metallic or made of one or more metals.

In particular, the base body may have a free area when viewed fromabove. A free area of the base body is understood to mean in particulara part of the surface of the base body uncovered by the shaped body. Thefree area may include a mounting surface configured for mounting thesemiconductor chip or a plurality of semiconductor chips. The mountingsurface can be only a partial region of the free area. While themounting surface is particularly uncovered by the reflective layer, thefree area can be covered by the reflective layer in places. For example,another partial region of the free area surrounding the mounting surfaceis covered by the reflective layer.

According to at least one embodiment of the component, the housing has afurther base body. In particular, the further base body may be laterallyspaced apart from the base body. Analogous to the base body, the furtherbase body can be laterally enclosed by the shaped body completely or inplaces. The further base body can have a further free area which isuncovered by the shaped body. In particular, the mounting surface isdifferent from the further free area of the further base body. Forexample, the additional free area is not intended for the assembly ofradiation-emitting devices. However, other devices such as protectivediodes may be arranged on the further free area. The further free areamay be covered, in particular completely covered, by the reflectivelayer.

According to at least one embodiment of the component, the housing has acavity. In particular, the cavity of the housing is laterally enclosed,in particular completely enclosed, by the shaped body. For example, sidewalls of the cavity are formed by surfaces of the shaped body. The freearea of the base body can form a bottom surface of the cavity at leastin places. In other words, the free area of the base body can form apartial region of the bottom surface of the cavity.

According to at least one embodiment of the component, the shaped bodyis configured in such a way that it laterally surrounds the base body atleast in places, wherein at least in certain regions the shaped body andthe base body have the same vertical height. The shaped body and thebase body have the same vertical height if the vertical height of theshaped body and the vertical height of the base body are the same withinthe manufacturing tolerances. In particular, the vertical height of theshaped body may differ from the vertical height of the base body by atmost 1%, 3% or 5%.

According to at least one embodiment of the component, the shaped bodyis flush with the base body along one or several lateral directions. Inparticular, the shaped body does not vertically protrude or does notsignificantly protrude above the base body, for example, on the sides ofthe free area.

If the shaped body and the base body have substantially the samevertical heights or if the shaped body is flush with the base body inone or several lateral directions, the shaped body may not form a cavitywhose bottom surface is formed at least in places by the free area ofthe base body. In this case, the shaped body may not protrude beyond thefree area of the base body and thus does not form a cavity of thehousing on the free area of the base body.

According to at least one embodiment of the component, the shaped bodycan be contiguous and, in particular, one-piece. Preferably, the shapedbody differs from the reflective layer. In other words, the shaped bodyand the reflective layer can have different material compositions. Inparticular, the shaped body is void of radiation-reflective particles orhas a reflectance lower than a reflectance of the reflective layer by atleast 5%, 10%, 20%, 30% or 40%. For example, the shaped body can beformed to be radiation-absorptive.

Alternatively, it is possible for the shaped body to be formed from areflective material. For example, the shaped body can be made of amatrix material, such as silicone or epoxy material, having whiteparticles embedded therein. Such shaped bodies or housings usually havea reflectance of 92%, 90%, 80% or 70% at most. By covering with thereflective layer, the reflectance of the shaped body or housing can beincreased by several percentage points, for example, by at least 3%, 5%,10%, 20% or 30%. The semiconductor chip is located for instance insidethe cavity of the housing. The reflective layer can partially orcompletely cover a bottom surface and/or side walls of the cavity.

According to at least one embodiment of the component, the free area ora bottom surface of the cavity comprises a mounting area for thesemiconductor chip or for a plurality of semiconductor chips. Themounting surface is thus part of the free area and/or the bottom surfaceof the cavity. Within the cavity, the semiconductor chip is located forinstance on the mounting surface. The free area and/or bottom surfacecan be partially covered by the reflective layer. Preferably, thesemiconductor chip and/or the mounting surface are/is free of a coveringby the reflective layer.

According to at least one embodiment of the component, it has a boundaryelement. In particular, the mounting surface may be completely orpartially enclosed by the boundary element. In particular, the boundaryelement may be adjacent to the reflective layer. In a plan view, thereflective layer can partially or completely cover the boundary element.The boundary element may be configured to prevent the mounting surfaceand/or the semiconductor chip from being covered by the reflectivelayer.

In a plan view of the mounting surface or the bottom surface of thecavity, the semiconductor chip may be laterally spaced from thereflective layer. Both a front side facing away from the mountingsurface and side surfaces of the semiconductor chip can be free of acovering by the reflective layer. For example, the semiconductor chip isa volume emitter, wherein radiation emitted during operation of thesemiconductor chip can be coupled out from the semiconductor chip notonly via the front side but also via the side surfaces. The componentcan have a plurality of semiconductor chips arranged on the mountingsurface. In particular, the mounting surface is the part of the bottomsurface which is surrounded, in particular completely surrounded, by theboundary element.

In at least one embodiment of the component, it has a semiconductorchip, a housing and a reflective layer. The housing may have a shapedbody and a base body, wherein the shaped body laterally surrounds thebase body at least in places and is different from the reflective layer.In a plan view, the base body may have a free area which is not coveredby the shaped body and may comprise a mounting surface for thesemiconductor chip, wherein the semiconductor chip is arranged on themounting surface. The free area may be partially covered by thereflective layer. The mounting surface is enclosed by a boundary elementat least in places, wherein the boundary element adjoins the reflectivelayer and may be configured to prevent the semiconductor chip from beingcovered by the reflective layer.

In a further embodiment of the component, the housing has a cavity,wherein the shaped body surrounds the cavity of the housing laterallyand is different from the reflective layer. The cavity has a bottomsurface having a mounting surface for the semiconductor chip, whereinthe semiconductor chip is arranged in the cavity on the mountingsurface. In particular, the mounting surface is a partial region of thefree area of the base body, wherein the free area can in turn be apartial region of the bottom surface of the cavity. The bottom surfaceis partially covered by the reflective layer. The mounting surface isenclosed by a boundary element at least in places, wherein the boundaryelement adjoins the reflective layer and is configured to prevent thesemiconductor chip from being covered by the reflective layer.

The boundary element allows a material of the radiation-reflective layerto be kept away from the semiconductor chip or from the mountingsurface. In the case of a volume emitter, this is particularly useful,since the radiation emitted during operation of the semiconductor chipcan be coupled out on all uncovered surfaces of the semiconductor chip.Due to the presence of the boundary element, the reflective layer can beeasily applied onto the free area, the bottom surface and/or the sidewalls of the cavity. The reflective layer can be formed in the presenceof the semiconductor chip without the semiconductor chip being partiallycovered by the reflective layer. The semiconductor chip or the pluralityof semiconductor chips can first be attached to and/or electricallycontacted on the mounting surface, wherein even after the semiconductorchip has been attached and/or contacted, the reflective layer can stillbe applied to the free area and/or to the bottom surface or to the sidewalls of the cavity without the risk of undesired covering of thesemiconductor chip.

According to at least one embodiment of the component, the boundaryelement is a recess on the free area of the base body and/or of thebottom surface of the cavity. In this case, the mounting surface is avertically elevated surface of the free area and/or of the bottomsurface, wherein the mounting surface is completely or partiallysurrounded by the recess. Along a lateral direction, the recess mayextend from the mounting surface as far as a lateral margin line of thefree area and/or as far as a side wall of the cavity. It is possible forthe recess to extend along the lateral directions from the mountingsurface to two opposite or adjacent side walls of the cavity and/orlateral margin lines of the free area. In a plan view of the free areaor of the bottom surface, it is possible for the recess to be arrangedbetween the mounting surface and the margin lines of the free area orthe side walls of the cavity. In a plan view, the boundary element maybe laterally spaced both from the semiconductor chip and from all marginlines of the free area or from all side walls of the cavity.

A vertical direction is generally understood to mean a direction that isdirected transverse, in particular perpendicular, to the free area or tothe bottom surface or to the mounting surface. A lateral direction, onthe other hand, is a direction that runs along, in particular parallel,to the free area or to the bottom surface or to the mounting surface.The vertical direction and the lateral direction are in particularperpendicular to each other.

The recess may have a vertical depth and/or a lateral width between 10μm and 200 μm inclusive, for example, between 10 μm and 100 μminclusive, for instance about 50 μm. Since the mounting surface isvertically elevated with respect to the recess, the recess serves as acollecting basin for the material of the reflective layer. This preventsthe material of the reflective layer from creeping onto the mountingsurface or onto the semiconductor chip.

The mounting surface is particularly preferred to be connected to abottom surface of the recess via an intermediate surface extending alongthe vertical direction, wherein the intermediate surface is convexly orconcavely curved. Alternatively, it is possible that the intermediatesurface forms an acute angle with the bottom surface of the recesscovered by the reflective layer. The acute angle can be between 20° and80° inclusive or between 30° and 70° inclusive. Such an inclined orcurved intermediate surface additionally prevents the material of thereflective layer from creeping up onto the mounting surface.

According to at least one embodiment of the component, the mountingsurface has the highest vertical elevation of the free area and/or ofthe bottom surface. In other words, the free area of the base bodyand/or the bottom surface of the cavity do/does not comprise a partialregion that is on the same vertical level as the mounting surface and/orprojects vertically beyond the mounting surface. The mounting surfacecan project beyond the boundary element in the vertical direction.Electromagnetic radiation emitted laterally from the semiconductor chipcan impinge onto the reflective layer directly without being partiallyabsorbed beforehand.

According to at least one embodiment of the component, the boundaryelement is an elevation on the free area and/or on the bottom surface.The boundary element is in particular a local vertical elevation. Inparticular, the mounting surface is laterally surrounded by theelevation completely. In particular, the boundary element protrudesbeyond the mounting surface. The elevation has a vertical height whichis, for example, between 10 μm and 200 μm inclusive, for instancebetween 10 μm and 100 μm inclusive. The boundary element thus has theeffect of a dam that is configured to protect the mounting surface orthe semiconductor chip from being covered by the material of thereflective layer.

According to at least one embodiment of the component, the boundaryelement is located between the mounting surface and a lateral marginline of the free area and/or a side wall of the cavity. The boundaryelement may be laterally spaced from the lateral margin line or fromseveral, for instance from all margin lines of the free area, or fromthe side wall of the cavity or from several, for instance from all theside walls of the cavity. Alternatively, if the boundary element is arecess, the recess may extend along a lateral direction from themounting surface as far as a lateral margin line of the free area and/oras far as a side wall of the cavity.

According to at least one embodiment of the component, the boundaryelement is laterally spaced from the semiconductor chip. In a plan viewof the free area or of the bottom surface, the boundary element and thesemiconductor chip are thus free of overlaps. The mounting surface canbe completely surrounded by the boundary element in lateral directions.In a plan view of the free area, the semiconductor chip and thereflective layer can be free of overlaps.

According to at least one embodiment of the component, the reflectivelayer has a matrix material and white particles embedded therein. Inparticular, at least 30% by volume and/or weight of the reflective layermay be accounted for by the white particles. The matrix material cancontain silicone or consist of silicone. The white particles arepreferably titanium oxide particles, such as TiO₂ particles, which areembedded in a matrix material preferably made of silicone.

A reflective layer formed from TiO₂ is particularly suitable forreflecting visible light, especially blue light. It has been shown thatsilver layers can have a reflectance of up to 96% or 98% with respect toelectromagnetic radiation in the visible spectral range, for example,with respect to the reflection of white light. Using TiO₂ particles, areflectance of up to 96% can be achieved. In the blue spectral range,the silver layers can have a reflectance of up to 95%. Using TiO₂particles, however, a reflectance of the reflective layer with respectto electromagnetic radiation in the blue spectral range of up to 98% andhigher can be achieved. Compared to a silver layer, the reflectance of aTiO₂-based reflective layer can be increased by about 3-4%. Moreover,such a reflective layer is hardly susceptible to corrosion.

According to at least one embodiment of the component, the semiconductorchip is a volume emitter, wherein during operation of the component,electromagnetic radiation generated by the semiconductor chip can becoupled out from the semiconductor chip via a front side facing awayfrom the mounting surface and via all side surfaces of the semiconductorchip. Since the entire surface of the semiconductor chip is free of areflective material, the electromagnetic radiation can be coupled outfrom the semiconductor chip essentially without absorption or reflectionlosses.

The semiconductor chip can have a carrier and a semiconductor bodyarranged thereon. The carrier can be radiation-transmissive. Forexample, the carrier is a sapphire substrate. The semiconductor body canbe based on a III-V or II-VI compound semiconductor material. Inparticular, the semiconductor chip has an optically active zone that isconfigured to emit electromagnetic radiation in the visible, ultravioletor infrared spectral range.

According to at least one embodiment of the component, the housing hasat least one or several leadframes. In particular, the leadframes aremade of a metal, for example, of copper. The base body of the housingcan form a leadframe. For example, the further base body forms a furtherleadframe of the housing. The leadframe and the further leadframe can beassigned to different electrical polarities of the component.

The leadframe and the further leadframe can be surrounded by the shapedbody in such a way that a surface of the housing facing thesemiconductor chip, in particular the bottom surface of the cavity, isformed regionally by surfaces of the leadframe and regionally bysurfaces of the shaped body. In particular, the housing has exactly twoleadframes, each of which is assigned to one of the electricalpolarities of the component. It is possible for the leadframe, which isformed for instance by the base body of the housing, to have a free areathat encompasses the entire mounting surface. In a plan view, theradiation-emitting semiconductor chip or the plurality ofradiation-emitting semiconductor chips arranged on the mounting surfacecan have overlaps only with a single leadframe.

According to at least one embodiment of the component, the boundaryelement, in particular the recess of the boundary element, has an areaof spreading or a plurality of areas of spreading. For example, the areaof spreading is located at a corner region or at a side region of themounting surface. The area of spreading can be rectangular, round orcurved, at least in places. If the boundary element has a plurality ofareas of spreading, the areas of spreading may be laterally spaced fromeach other. For example, the areas of spreading are located at differentcorner regions or at different side regions of the mounting surface. Itis possible for the areas of spreading to be formed at least at two orat all corner regions and/or at least at two or at all side regions ofthe mounting surface.

In particular, the area of spreading is part of the recess and serves asa collecting basin for the material of the reflective layer. Forexample, the area of spreading has a lateral width which is at least 1.5times, twice, three times or at least five times as large as a lateralwidth of the subregions of the recess adjacent to the area of spreading.The lateral width is determined in particular transversely orperpendicularly to the local orientation of the recess. For example, aratio of the width of the area of spreading to the width of thesubregions of the recess adjacent to the area of spreading is between1.5 and 10 inclusive, for instance between 1.5 and 6 inclusive, forexample, between 1.5 and 4 inclusive.

According to at least one embodiment of the component, the reflectivelayer has at least a first partial layer and a second partial layer. Inparticular, the first partial layer does not cover or only partiallycovers the boundary element, in particular the recess. Outside themounting surface and the recess, the first partial layer may partiallyor completely cover the free area and/or the side walls of the cavity.The second partial layer can partially or completely cover the boundaryelement, in particular the recess. The second partial layer cancompletely fill the recess. In particular, the second partial layer isdirectly adjacent to the first partial layer.

For example, the reflective layer is produced in a two-step process. Inparticular, the first partial layer of the reflective layer is stoppedat an outer edge of the boundary element, in particular of the recess.The boundary element can be free of a material of the first partiallayer. However, it is possible that the boundary element formed as arecess is partially covered by the first partial layer.

After the formation of the first partial layer, in particular after thecuring of the material of the first partial layer, the second partiallayer can be applied onto the boundary element, in particular onto therecess. The recess may be completely covered by the second partiallayer. For example, the material of the second partial layer isintroduced into the recess at an area of spreading or at the areas ofspreading. The area of spreading or the plurality of areas of spreadingthus facilitates the filling of the recess. The second partial layer candirectly adjoin the first partial layer. It is possible that the firstpartial layer is partially covered by the second partial layer whenviewed from above. The first partial layer and the second partial layercan be made of the same material or of different materials. The firstpartial layer and the second partial layer may differ from each other intheir material composition, viscosity and/or wettability.

In at least one embodiment of a method for producing a component, thesemiconductor chip is attached to the mounting surface. Preferably, thefree area or the bottom surface is partially covered by the reflectivelayer only after the semiconductor chip has been attached.

Furthermore, it is preferred that the reflective layer is applied forinstance onto the side walls of the cavity only after the semiconductorchip has been attached to the mounting surface. The application of thereflective layer onto the free area and/or onto the bottom surfaceand/or onto the side walls of the cavity can be carried out in a commonprocess step. For example, a material of the reflective layer is sprayedor injected onto the free area of the base body or the further base bodyand/or onto the bottom surface and/or onto the side walls of the cavity.After the reflective layer has been formed, electrical conductor tracks,which are arranged or formed on the free area or on the bottom surfacemay be partially or completely covered by the reflective layer.

According to at least one embodiment of the method, a material of thereflective layer is applied in liquid form, in particular in viscousform, onto the free area or onto the bottom surface and/or onto the sidewalls of the cavity. The material of the reflective layer may containwhite particles, wherein at least 30% by volume and/or weight of thereflective layer may be accounted for by the white particles. Theproportion of white particles may be between 30% and 90% inclusive, 30%and 70%, 30% and 50%, 40% and 60% inclusive, or between 40% and 80%inclusive of the volume and/or weight of the reflective layer.

The method described above is particularly suitable for the productionof a component described here. The features described in connection withthe component can therefore be used for the method and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, preferred embodiments and further developments ofthe component or of the method will become apparent from the exemplaryembodiments explained below in conjunction with FIGS. 1A to 3D and 4A to4C.

FIGS. 1A and 1B show schematic illustrations of comparative examples fora component without a boundary element;

FIGS. 2A and 2B show schematic illustrations of exemplary embodimentsfor a component having a boundary element;

FIGS. 3A, 3B, 3C and 3D show schematic illustrations of furtherexemplary embodiments for a component having a boundary element; and

FIGS. 4A, 4B and 4C show schematic illustrations of further exemplaryembodiments for a component having a boundary element.

Identical, equivalent or equivalently acting elements are indicated withthe same reference numerals in the figures. The figures are schematicillustrations and thus not necessarily true to scale. Comparativelysmall elements and particularly layer thicknesses can rather beillustrated exaggeratedly large for the purpose of better clarification.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1A schematically shows a comparative example for a component 10having a housing 9 and at least one semiconductor chip 1 along a cuttingline AA′ (see FIGS. 1B and 2B), wherein the semiconductor chip 1 isarranged in a cavity 8 of the housing 9.

The housing 9 has a base body 91 and a shaped body 90. A bottom surface80 of the cavity 8 is formed in particular by a surface of the base body91, for instance by a free area 80A of the base body 91, wherein in aplan view, the free area 80A or the bottom surface 80 is not covered bythe shaped body 90. The free area 80A or the bottom surface 80 isdelimited in one or several lateral directions by one or several marginlines 80R or by one or several side walls 82 of the cavity 8. The sidewalls 82 of the cavity 8 are formed in particular by inclined surfacesof the shaped body 90. The side walls 82 may have an angle ofinclination to the bottom surface 80 between 20° and 70° inclusive, forinstance between 30° and 60°, inclusive.

The free area 80A or the bottom surface 80 has a mounting area 81, onwhich the semiconductor chip 1 is arranged. The component 10 can haveseveral semiconductor chips 1 arranged next to each other on themounting surface 81. In particular, the semiconductor chips 1 areconfigured to generate electromagnetic radiation. The semiconductorchips 1 can be connected in series or parallel to each other. Thesemiconductor chips 1 each have a front side 11 facing away from themounting surface 81, a rear side 12 facing the mounting surface 81 andside surfaces 13. In particular, the semiconductor chip 1 or thesemiconductor chips 1 is/are (a) light-emitting diode/s. Electromagneticradiation generated by the semiconductor chip 1 during operation of thecomponent 10 can be coupled out from the semiconductor chip 1 via thefront side 11 and/or the side surfaces 13 of the semiconductor chip 1.

The cavity 8 is filled in particular by a coating 6. In a plan view, thecoating can completely cover the semiconductor chip 1 or thesemiconductor chips 1. The coating may contain phosphors that convertshort-wave spectral ranges of the radiation emitted by the semiconductorchip 1 into long-wave spectral ranges of electromagnetic radiation. Inaddition or alternatively, the coating 6 may contain scatteringparticles.

The component 10 has a front side 101, a rear side 102 and side surfaces103. The light generated during operation of the component 10 can becoupled out from the component 10 at the front side 101. For increasingthe efficiency of the component 10, inner surfaces of the cavity 8 canbe configured to reflect radiation. For this purpose, a material of theshaped body 90 can have reflective or scattering particles, so that theside walls 82 of the cavity 8 are configured to be reflective. However,since the material of the shaped body 90 has to meet furtherrequirements, particularly with regard to mechanical stability, only aninsufficient degree of reflection is achieved at the side walls 82. Forincreasing the reflectivity of the bottom surface 80, it canalternatively be coated with a reflective metal layer. However, metallayers are susceptible to corrosion, so that the degree of reflection ofthe bottom surface decreases rapidly over time. In addition, a metalcoating of the bottom surface 80 and/or of the side walls 82 can lead toan increased risk of short circuits.

The exemplary embodiment for a component 10 shown in FIG. 1B essentiallycorresponds to the exemplary embodiment shown in FIG. 1A. In contrast tothis, FIG. 1B shows that the housing 9 has a second base body 92 inaddition to the first base body 91. In particular, the base bodies 91and 92 are assigned to different polarities of the component 10. Thefirst base body 91 and the second base body 92 can form a firstleadframe 91 or a second leadframe 92 of the housing 9.

The base bodies 91 and 92 are surrounded by the shaped body 90 in such away that the base bodies 91 and 92 are held together by the shaped body90. In particular, the shaped body 90 has an intermediate region 93which is arranged between the base bodies 91 and 92 and mechanicallyconnects the first base body 91 to the second base body 92. The firstbase body 91 has a first free area 80A. The second base body 92 has afurther, namely a second free area 80B. The further free area 80B isdelimited for instance in one or several lateral directions by one orseveral margin lines 80S or by one or several side walls 82 of thecavity 8.

In a plan view, the free areas 80A and 80B are not covered by the shapedbody 90. The first base body 91 and/or the second base body 92 can havefurther partial surfaces which adjoin the free area 80A or 80B and arecovered by the shaped body 90. The first base body 91 and/or the secondbase body 92 can extend laterally into the shaped body 90 and beanchored to the shaped body 90.

The bottom surface 80 of the cavity 8 is formed regionally by surfacesof the base bodies 91 and 92 and regionally by surfaces of theintermediate region 93 of the shaped body 90. As shown in FIG. 1B, theintermediate region 93 forms a local vertical elevation within thecavity 8. The intermediate region 93 extends along a lateral directionbetween two opposite side walls 82 of the cavity 8. If a reflectivematerial is applied onto the side walls 82, the intermediate region 93of the shaped body 90 cannot prevent the reflective material fromreaching the mounting surface 81 or the semiconductor chips 1. Thus, theintermediate region 93 shown in FIG. 1B is not to be regarded as aboundary element.

The first base body 91 and the second base body 92 can be electricallycontacted externally, in particular via the first connection point(s)910 and/or the second connection point(s) 920 on the side surfaces 103of the component 10 or of the housing 9. Deviating from this, it ispossible that the connection point(s) 910 and/or 920 are/is freelyaccessible at the rear side 102, in particular exclusively at the rearside 102 of the component 10, so that the component 10 is electricallyconnectable via the rear side 102.

A surface of the first base body 91 exposed within the cavity 8 formsthe mounting surface 81 for the semiconductor chips 1. The component 10has a protective diode 7 which is arranged within the cavity 8 on asecond free area 80B of the second base body 92. The protective diode 7is not arranged on the mounting surface 81 for the semiconductor chips 1but on the second free area 80B of the second base body 92, wherein thesecond free area 80B is different from the first free area 80Acomprising the mounting surface 81. The first free area 80A and thesecond free area 80B are laterally spaced apart from each other inparticular by the intermediate region 93 of the shaped body 90. Thesecond free area 80B is delimited in lateral directions by furthermargin lines 80S, wherein the further margin lines 80S are boundarylines between the second free area 80B and the shaped body. Thesemiconductor chips 1 and the protective diode 7 can be electricallyconnected to the base bodies 91 and 92 via electrical connections 5 forinstance in the form of bonding wires. For example, the protective diode7 is connected in parallel or anti-parallel to the semiconductor chips1.

The exemplary embodiment for a component 10 shown in FIG. 2A along acutting line AA′ (see FIG. 2B) essentially corresponds to the exemplaryembodiment shown in FIG. 1A. All features disclosed in connection withFIG. 1A can therefore be used for the exemplary embodiment shown in FIG.2A.

In contrast to FIG. 1A, the component 10 shown in FIG. 2A has a boundaryelement 3. The boundary element 3 is a recess 31 which—in a plan view ofthe bottom surface 80—completely or partially encloses the mountingsurface 81. The mounting surface 81 adjoins in particular directly to anedge of the recess 31. The bottom surface 80 has one step having anupper terrace formed by the mounting surface 81 and a lower terraceformed by the surface of the recess 31. For example, a vertical distancebetween the upper and the lower terraces is between 10 μm and 200 μminclusive, for instance between 10 μm and 100 μm inclusive.

As shown in FIG. 2A, the side walls 82 of the cavity 8 are covered, inparticular completely covered by a reflective layer 2. The reflectivelayer 2 partially or completely covers the free area 80A and/or thebottom surface 80 especially in the regions of the recess/recesses 31.The mounting surface 81 and/or the semiconductor chip 1 or thesemiconductor chips 1 are free of a covering by the reflective layer 2.Due to the edges or steps formed on the mounting surface 81, theboundary element 3 prevents the material of the reflective layer 2 fromcreeping onto the mounting surface 81 or onto the semiconductor chips 1.

The reflective layer 2 can have a matrix material and white particlesembedded therein. The proportion of white particles may be at least 30%,40%, 50%, 60%, 70% or up to 90% of the volume and/or weight of thereflective layer 2. The matrix material can contain silicone or consistof silicone. The white particles may contain one of the followingmaterials TiO₂, BaSO₄, ZnO, alumina or ZrO₂ or consist of one of thesematerials. The proportion of white particles can be adjusted in such away that the reflective layer has a reflectance of at least 70%, 80%,90%, 95% or at least 98% with respect to visible light.

The coating 6 and/or the reflective layer 2 may contain silicone. Thecoating 6 directly adjoins the reflective layer 2. In this case, theadhesion between the coating 6 and the reflective layer 2 is increasedin comparison with the adhesion between the coating 6 and the shapedbody 90, which usually has an epoxy material. However, it is alsopossible that the material of the shaped body 90 is a mixture of asilicone and an epoxy, namely a so-called silicone-epoxy hybrid materialor a so-called silicone-mold-compound of silicone and white reflectivefillers. If a reflective layer 2 is arranged on the side walls 82, theshaped body 90 can be free of reflective particles.

According to FIG. 2A, the base body 91 is externally electricallyconnectable at a first connection point 910 on the side surface 103 ofthe housing 9 or of the component 10. Along the lateral direction, thebase body 91 can thus extend throughout the shaped body 90. It is alsopossible for the base body 91 to extend along the vertical directionthroughout the shaped body 90 so that the base body 91 is electricallyconnectable particularly at the rear side 102 of the housing 9 or of thecomponent 10.

The exemplary embodiment for a component 10 shown in FIG. 2B essentiallycorresponds to the exemplary embodiment shown in FIG. 1B. All featuresdisclosed in connection with FIG. 1B can be used for the component 10shown in FIG. 2B and vice versa. In contrast to FIG. 1B, the component10 shown in FIG. 2B has a boundary element 3 in particular in the formof a recess 31. Compared to the recess 31, the mounting surface 81 isvertically elevated. The recess 31 can be formed by an etching process.The etching depth can be between 10 μm and 200 μm inclusive, forinstance between 10 μm and 100 μm inclusive, for example, about 50 μm.

As shown in FIG. 2B, the recess 31 extends along the lateral directionsfrom the mounting surface 81 to the side walls 82 of the cavity 8 or tothe first margin lines 80R of the first free area 80A. The first marginlines 80R are in particular boundary lines between the first free area80A and the shaped body 90. The recess 31 extends along one lateraldirection between the mounting surface 81 and the intermediate region 93of the shaped body 90. If the side walls 82 and the bottom surface 80 ofthe cavity or the free area 80A are covered with a reflective material,the recess 31 can serve as a collecting basin for the reflectivematerial and thus prevent the reflective material from reaching themounting surface 81 or the semiconductor chips 1.

All side walls 82 of the cavity 8 may be partially or completely coveredby the reflective layer 2. Besides the mounting surface 81 for thesemiconductor chips 1, the bottom surface 80 or the free area 80A can becompletely covered by the reflective layer 2. For reasons of clarity,the reflective layer 2 is not shown in FIG. 2B. In particular, at least10%, 20%, 30% or at least 40% of the total bottom surface 80 or of thefree area 80A may be covered by the reflective layer 2. For example, thecovered proportion of the bottom surface 80 or of the free area 80A maybe between 10% and 70% inclusive or between 10% and 50% inclusive.

FIG. 3A shows a component 10 according to another exemplary embodiment.In this case, the shaped body 90 encloses the base body/bodies 91 and/or92 in particular in such a way that the shaped body 90, for instance theintermediate region 93, and the base body/bodies 91 and/or 92 havesubstantially the same vertical heights. For example, along the lateraldirection, the first free area 80A and/or the second free area 80Bare/is flush with the shaped body 90 or with the intermediate region 93of the shaped body 90. In particular, the shaped body 90 is free of acavity in which the semiconductor chip 1 is arranged. In other words,the shaped body 90, especially at its edges, does not project beyond thefirst free area 80A and/or the second free area 80B.

The first base body 91 and/or the second base body 92 can have a partialregion which extends throughout the shaped body 90 and is electricallyconnectable at the rear side 102 of the housing 9 or of the component10. As shown in FIG. 3A, the component 10 has a first connection point910 and a second connection point 920 on the rear side 102. The firstconnection point 910 is in particular part of the first base body 91,the second connection point 920 is in particular part of the second basebody 92.

In deviation from FIG. 3A, it is possible that the shaped body 90completely surrounds the first base body 91 and/or the second base body92 in the lateral directions such that the side surfaces 103 of thecomponent 10 are free of the first base body 91 and/or of the secondbase body 92. The component 10 can be externally electricallyconnectable only at the rear side 102 via the first connection point 910and/or via the second connection point 920. In addition, it is alsopossible for the shaped body 90 to be flush with the first base body 91and/or with the second base body 92 at the margin lines 80R and/or 80S.In this case, the shaped body 90 and the first base body 91 and/or thesecond base body 92 can have the same vertical height at the marginlines 80R and/or 80S.

According to FIG. 3A, the mounting surface 81 is formed exclusively by asurface of the first base body 91. In particular, the first free area80A is formed by the entire surface of the first base body 91 facing thesemiconductor chip 1. The lateral expansion of the first free area 80Ais limited by the first margin lines 80R and the intermediate region 93of the shaped body 90. The second free area 80B can be formed by theentire surface of the second base body 92 facing the semiconductor chip1. The lateral extent of the second free area 80B is limited by thesecond margin lines 80S and the intermediate region 93 of the shapedbody 90.

The boundary element 3 in FIG. 3A is a local vertical recess 31 of thefirst base body 91. In a plan view of the first free area 80A, the localrecess 31 is laterally spaced apart from the intermediate region 93 ofthe shaped body 90, from the second base body 92 or from all marginlines 80R. The reflective layer 2 is located only in the regions of thelocal recess 31 or of the local recesses 31. The local recess 31 or theplurality of recesses 31 can be contiguous. In a plan view of the firstfree area 80A, the local recess 31 can completely or partially enclosethe mounting surface 81.

According to the exemplary embodiment for a component 10 shown in FIG.3A, the semiconductor chip 1 is attached to the mounting surface 81 bymeans of a connecting layer 4. The connecting layer 4 is, for example,an adhesive layer or a bonding layer. The connecting layer 4 can beelectrically insulating. The semiconductor chip can be electricallyconnected to the base bodies 91 and 92 via electrical connections 5, inparticular in the form of bonding wires 5.

The exemplary embodiment for a component 10 shown in FIG. 3B essentiallycorresponds to the exemplary embodiment shown in FIG. 3A. In contrast tothis, the shaped body 90 has a cavity 8. The component 10 shown insectional view in FIG. 3B can be the component 10 shown in FIG. 2B alongthe cutting line BB′. The reflective layer 2 covers in particular notonly the local recess 31, but also other regions of the bottom surface80 or of the free area 80A outside the mounting surface 81. Thereflective layer 2 can partially or completely cover the intermediateregion 93 of the shaped body 90 and/or a second free area 80B of thesecond base body 92 located inside the cavity 8. All side walls 82 mayalso be partially or completely covered by the reflective layer 2. Thereflective layer 2 can be formed to be contiguous.

In FIG. 3B, the side walls 82 are oriented essentially perpendicular tothe bottom surface 80. In deviation from this, it is also possible forthe side walls 82 to have an angle of inclination for instance between20° and 70° with respect to the bottom surface 80. In contrast to FIGS.3A and 3B, it is also possible for the semiconductor chip 1 to beelectrically connectable for instance partially via its rear side 12. Inthis case, the semiconductor chip 1 can be electrically connected to thefirst base body 91 by an electrically conductive connecting layer 4. Forexample, the connecting layer 4 is a solder layer.

The exemplary embodiment for a component 10 shown in FIG. 3C essentiallycorresponds to the exemplary embodiment shown in FIG. 1A. In contrast tothis, the component 10 has a boundary element 3 on the bottom surface 80of the cavity 8 or on the free area 80A. The boundary element 3 is alocal elevation 32. The local elevation 32 can completely or partiallyenclose the mounting area 81. The local elevation 32 can have a verticalheight between 10 μm and 200 μm inclusive. Along the vertical direction,the local elevation protrudes in particular over the free area 80A orover the bottom surface 80 and/or over the mounting area 81. The localelevation 32 may have a mushroom-like structure. The local elevation 32has the function of a dam that keeps a material of reflective layer 2away from the mounting surface 81 or from the semiconductor chips 1.

The local elevation 32 can have a material that is different from thematerial of the base body 91. For example, the local elevation 32 can bea lacquer layer. Alternatively, it is also possible that the localelevation 32 is part of the base body 91. Together, the local elevation32 and the base body 91 can be formed in one piece. For example, thebase body 91 is etched in such a way that it comprises the localelevation 32.

According to FIG. 3C, the reflective layer 2 completely covers the sidewalls 82 of the cavity 8. The reflective layer 2 adjoins the free area80A, the bottom surface 80, the boundary element 3, the coating 6 andthe side walls 82. In particular, the reflective layer 2 and the shapedbody 90 are made of different materials. In particular, the material ofthe shaped body 90 is free of white particles, which are particularlycontained in the reflective layer 2.

The exemplary embodiment shown in FIG. 3D essentially corresponds to theexemplary embodiment for a component 10 shown in FIG. 3C. Unlike FIG.3C, wherein the component 10 is electrically connectable at a firstconnection point 910 on the side surface 103, according to FIG. 3D, thefirst connection point 910 is located at the rear side 102 of thecomponent 10. The first base body 91 can have a partial region whichextends in the vertical direction throughout the shaped body 90 and isfreely accessible at the rear side 102 of the housing 9 or of thecomponent 10. In lateral directions, the first base body 91 can becompletely enclosed by the shaped body 9o. The component 10 can have asecond base body 92 which is formed similar to the first base body 91and has a second connection point 920 at the rear side 102.

FIG. 4A shows the component 10 in a plan view. In particular, theexemplary embodiment shown in FIG. 4A corresponds to the exemplaryembodiment for a component 10 shown in FIG. 3B. According to FIG. 4A,the boundary element 3, in particular the recess 31, has an area ofspreading 33. The area of spreading 33 is thus a local spreading of therecess 33. The area of spreading 33 is arranged on one side region ofthe mounting surface 81. In contrast to FIG. 4A, the boundary element 3can have a plurality of areas of spreading 33.

The exemplary embodiment shown in FIG. 4B essentially corresponds to theexemplary embodiment shown in FIG. 4A. In contrast, the recess 31 has aplurality of areas of spreading 33 which are formed at the cornerregions of the mounting surface 81. In contrast to FIGS. 4A and 4B, theboundary element 3 can have areas of spreading 33 both on the sideregions and on the corner regions of the mounting surface 81.

According to FIG. 4C, the reflective layer 2 has a first partial layer21 and a second partial layer 22. In particular, the first partial layer21 adjoins the recess 31. Alternatively, the first partial layer 21 maypartially cover the recess 31. Outside the mounting surface 81 and therecess 31, the first partial layer 21 can partially or completely coverthe free area 80A of the base body 91 or of the shaped body 90 and/orthe side walls 82 of the cavity. The second partial layer 22 maypartially or completely cover or fill the recess 31, in particular thearea of spreading 33 or the areas of spreading 33. The first partiallayer 21 and the second partial layer 22 can be made of the samematerial or of different materials.

By means of a boundary element surrounding a mounting surface, areflective material can be reliably applied onto areas around themounting surface without the reflective material reaching the mountingsurface. Before the reflective layer has been formed, a semiconductorchip, which is in particular a volume emitter, can be attached to themounting surface without the risk of being covered by the reflectivematerial of the reflective layer.

The invention is not restricted to the exemplary embodiments by thedescription of the invention made with reference to exemplaryembodiments. The invention rather comprises any novel feature and anycombination of features, including in particular any combination offeatures in the claims, even if this feature or this combination is notitself explicitly indicated in the claims or exemplary embodiments.

What is claimed is:
 1. A component comprising: a semiconductor chip; ahousing; and a reflective layer, wherein the housing has a shaped bodyand a base body, wherein the shaped body laterally encloses the basebody at least in places and is different from the reflective layer,wherein, in a plan view, the base body has a free area which isuncovered by the shaped body and comprises a mounting surface for thesemiconductor chip, wherein the semiconductor chip is arranged on themounting surface, wherein the free area is partially covered by thereflective layer, wherein the mounting surface is enclosed at least inregions by a boundary element which adjoins the reflective layer and isconfigured to prevent the semiconductor chip from being covered by thereflective layer, and wherein the boundary element is a recess on thefree area, wherein the boundary element is located between the mountingsurface and a lateral margin line of the free area, and wherein theboundary element is laterally spaced from the lateral margin line of thefree area.
 2. The component according to claim 1, wherein, in the planview, the reflective layer completely covers the recess and the mountingsurface is connected to a bottom surface of the recess via anintermediate surface extending along a vertical direction, and whereinthe intermediate surface is convexly or concavely curved.
 3. Thecomponent according to claim 1, wherein, in the plan view, thereflective layer completely covers the recess and the mounting surfaceis connected to a bottom surface of the recess via an intermediatesurface extending along a vertical direction, and wherein theintermediate surface forms an acute angle with the bottom surface of therecess covered by the reflective layer.
 4. The component according toclaim 1, wherein the shaped body has a cavity and the free area forms abottom surface of the cavity at least in places.
 5. The componentaccording to claim 1, wherein the shaped body laterally surrounds thebase body in such a way that the shaped body and the base body have atleast in places the same vertical height or that the shaped body isflush with the base body along at least one lateral direction.
 6. Thecomponent according to claim 1, wherein the recess of the boundaryelement has an area of spreading which is located at a corner region orat a side region of the mounting surface.
 7. The component according toclaim 6, wherein the area of spreading serves as a collecting basin fora material of the reflective layer and the area of spreading has alateral width which is at least 1.5 times as large as a lateral width ofsubregions of the recess adjacent to the area of spreading.
 8. Thecomponent according to claim 1, wherein the reflective layer comprises afirst partial layer and a second partial layer, wherein the firstpartial layer does not cover or only partially covers the recessand—outside the mounting surface and the recess—completely covers thefree area, and wherein the second partial layer fills the recess anddirectly adjoins the first partial layer.
 9. The component according toclaim 1, wherein the boundary element is laterally spaced from thesemiconductor chip so that, in the plan view of the free area, theboundary element and the semiconductor chip are free of overlaps. 10.The component according to claim 1, wherein the mounting surface iscompletely surrounded by the boundary element in lateral directions. 11.The component according to claim 1, wherein, in the plan view of thefree area, the semiconductor chip and the reflective layer are free ofoverlaps.
 12. The component according to claim 1, wherein the reflectivelayer comprises a matrix material and white particles embedded therein,and wherein a proportion of at least 30 percent by volume and/or byweight of the reflective layer is accounted for by the white particles.13. The component according to claim 12, wherein the matrix material isa silicone and the white particles are TiO₂ particles.
 14. The componentaccording to claim 1, wherein the semiconductor chip is a volumeemitter, and wherein the semiconductor chip is configured to couple outelectromagnetic radiation generated by the semiconductor via a frontside facing away from the mounting surface and via all side surfaces ofthe semiconductor chip.
 15. The component according to claim 1, whereinthe base body is surrounded by the shaped body in such a way that alongthe lateral direction the free area is flush with the shaped body inregions.
 16. A method for producing a component according to claim 1,the method comprising: fixing the semiconductor chip to the mountingsurface; and covering the free area in places by the reflective layeronly after the semiconductor chip has been fixed.
 17. The methodaccording to claim 16, further comprising: forming the shaped body suchthat it has a cavity; and after the semiconductor chip has been fixed tothe mounting surface, applying the reflective layer onto side walls ofthe cavity.
 18. The method according to claim 16, further comprisingapplying a material of the reflective layer in liquid form onto the freearea and/or onto side walls of a cavity formed in the shaped body,wherein the material of the reflective layer comprises white particles,and wherein a proportion of at least 30 percent by volume and/or byweight of the reflective layer is accounted for by the white particles.19. A component comprising: a semiconductor chip; a housing; and areflective layer, wherein the housing has a shaped body and a base body,wherein the shaped body laterally encloses the base body at least inplaces and is different from the reflective layer, wherein, in a planview, the base body has a free area which is uncovered by the shapedbody and comprises a mounting surface for the semiconductor chip,wherein the semiconductor chip is arranged on the mounting surface,wherein the free area is partially covered by the reflective layer,wherein the mounting surface is enclosed at least in regions by aboundary element which adjoins the reflective layer and is configured toprevent the semiconductor chip from being covered by the reflectivelayer, wherein the boundary element is an elevation on the free area,and wherein the boundary element projects beyond the mounting surface.20. The component according to claim 19, wherein the elevation is alocal elevation comprising a material which is different from thematerial of the base body.